IIRC his chief of staff was involved up to his neck and gave up Rommel to save himself.?
He was implicated by Gen. Beck and Goerdler, the Mayor of Leipzig. An intermediary was also quite damning to the Field Marshal. A Dr. Strolin, whom his wife and he were friends with. They even served together in WWI.
Rommel lost all respect for Hitler after el Alamein due to the Fuhrer’s disdain for Germany’s people. He never once bought into the assassination plot, only that Hitler should be arrested and brought to trial, specifically because his order’s grew more and more incoherent.